JSC2011-E-013877 (28 Jan. 2011) --- NASA astronauts Steve Bowen (foreground) and Alvin Drew, both STS-133 mission specialists, attired in training versions of their Extravehicular Mobility Unit (EMU) spacesuits, are submerged in the waters of the Neutral Buoyancy Laboratory (NBL) near NASA's Johnson Space Center. Divers are in the water to assist Bowen and Drew in their rehearsal, which is intended to help prepare them for work on the exterior of the International Space Station. Photo credit: NASA or National Aeronautics and Space Administration